That’s awesome, anon! It can sometimes be hard to make connections at college, and it’s great that you’ve been mingling.
Just be polite, and treat it as a raincheck instead of a flat-out rejection. “Hey man, I’m sorry, but I’m worn out. I need some me time. I’ll catch you later though, alright?”
You get the solitude you need, and they get the verification that a. you would like to spend time with them but b. you can’t and it isn’t their fault. Plus, you’re being completely honest.
If the constant texting and calling is wearing you out just hearing your phone, keep it on vibrate. People generally get the message after their calls keep going to voicemail It’s a little less polite, but then, calling somebody incessantly isn’t what I would call polite either.
I think it’s also worth considering that when people first go into a foreign environment where they don’t know anybody, they tend to latch onto a few people like drowning sailors cling to flotsam until they make friends of actual substance. The friends you make right away at college (generally, I find, roommates/floormates) often aren’t the friends that stick around- these are the ones you make later, through your classes or extracurriculars.
In the beginning, it’s less about having a genuine friendship than having somebody you can hang out with just to anchor yourself until you grow more comfortable. That’s been my observation, anyway.